A conventional cantilever type caliper brake which is well-known is disclosed in Japanese Utility Model Publication Gazette No. Sho 42-20,329, in which a pair of brake arms having brake shoes are supported rotatably to a pair of fixing bases fixed by welding to a front fork or a rear fork at the bicycle frame, and between the fixing bases and the brake arms are interposed a pair of return springs for biasing the brake arms in the direction of enlarging the distance between the brake shoes respectively, so that a control wire connected to a free end of each brake arm is pulled to swing each brake arm, thereby exerting the braking action.
The fixing bases at the caliper brake are welded to the bicycle frame at a factory and the brake arms, return springs and mounting screws for mounting the brake arms to the fixing bases are sold as separate parts, for example, as a set in one package. A store or a user mounts on the fixing bases prefixed to the bicycle frame through the mounting screws the brake arms while incorporating therein the return springs respectively, at which time a preload is applied to each return spring.
Such assembly of the brake arm while applying the preload to each return spring is very difficult for the store or the user.